The three major phenomena associated with supernovas explosions can be
demonstrated with easily available and inexpensive materials. The imploding can
and basketball/tennis ball demos are commonly used in physics classes; however
they are not usually associated with core contraction and the detonation of
stellar atmospheric layers. The most difficult concept for students to understand
is density. The angel cake and cellophane is a good approximation of the amount
of material that remains in the core and its size, and the amount of material
that gets blown away. Since all supernovas remnant images show all the
beautifully colored materials that have been blown away from the star and the
core cannot be seen - students have a common misconception that the star has
literally blown itself apart, which is not the case.